Substituted bisacyloxynaphthacenes

ABSTRACT

Compounds of the formula I ##STR1## in which R 1  to R 8  independently of one another are H and at least one of R 1  to R 8  is a substituent belonging to the group --F, --Si(C 1  -C 4  alkyl) 3  or --COOR 10  ; or each pair of adjacent radicals of R 1  to R 8  is --CO--O--CO--; or at least one of R 1  to R 8  is C 1  -C 20  alkyl--(X) p  --, C 2  -C 20  alkenyl--(X) p  --, C 2  -C 20  -alkynyl--(X) p  --, C 3  -C 8  cycloalkyl--(X) p  --, (C 1  -C 12  alkyl--C 3  -C 8  cycloalkyl--(X) p  --, C 3  -C 8  -cycloalkyl--CH 2  --(X) p  --, C 1  -C 12  alkyl--C 3  -C 8  cycloalkyl--CH 2  --(X) p  --, C 6  -C 10  aryl--X--, C 7  -C 20  alkaryl--X--, C 7  -C 12  aralkyl--(X) p  -- or C 8  -C 20  --alkaralkyl--(X) p  -- or --Y--(C m  H 2m  --O)-- n  R 10  each of which is unsubstituted or substituted by --F, --OH, --CN, C 1  -C 12  alkoxy, C 1  -C 12  acyloxy or --COOR 10  ; R 10  is H or C 1  -C 18  alkyl, X is --O--, --S--, --SO-- or --SO 2  -- and Y is --O-- or --S--, and p is 0 or 1, m is a number from 2 to 6 and n is a number from 2 to 20; and R 9  is C 1  -C 4  acyl which is unsubstituted or substituted by --F. The compounds are intermediates for the preparation of 5,6,11,12-tetrathiotetracenes which form electrically conducting charge-transfer complexes with electron donors.

The invention relates to 5,12-acyloxynaphthacenes which are substitutedin the 1-, 2-, 3-, 4-, 7-, 8-, 9-and/or 10-positions, to a process fortheir preperation and to a process for the preparation of unsubstitutedor correspondingly substituted 5,6,11,12-tetrathiotetracenes.

Naphthacene-5,11-diones are important intermediates in the preparationof tetrathiotetracenes and tetraselenotetracenes. Depending on thereaction conditions and the reaction time, the reduction of the dionesgives dihydrotetracenes, tetracenes or mixtures thereof. The tetracenescan be chlorinated to give 5,11-dichlorotetracenes or6,12-dichlorotetracenes.

The direct reaction of dihydrotetracene with sulfur givestetrathiotetracene in moderate yields [Ch. Marschalk, Bull. Soc. Chim.France pages 931 and 1122 (1939)]. The direct reaction of tetracenes anddichlorotetracenes with sulfur also gives tetrathiotetracenes [EP-A0,153,905 and Ch. Marschalk, Bull. Soc. Chim. France, page 427 (1948)].The preparation of tetrathiotetracenes of maximum purity by theseprocesses requires, inter alia, that pure tetracenes be used as thestarting materials. The reduction of naphthacenediones, however, oftengives mixtures with hydroxytetracenes and dihydroxytetracenes, and, inaddition, the yields are not satisfactory. In addition,hydroxytetracenes and dihydroxytetracenes do not react with sulfur togive tetrathiotetracenes.

5,12-Diacetoxytetracene has been described by T. Kametani in Chem.Pharm. Bull. 26(12), pages 3820-3824 (1978).

It has now been found that 5,12-diacyloxytetracenes can be reacteddirectly with sulfur to give 5,6,11,12-tetrathiotetracenes. The5,12-diacyloxytetracenes are accessible in this reaction in high yieldsand high states of purity by simple reductive acylation.

The invention relates to compounds of the formula I ##STR2## in which R¹to R⁸ independently of one another are H and at least one of R¹ to R⁸ isa substituent belonging to the group --F, --Si(C₁ -C₄ alkyl)₃ or--COOR¹⁰ ; or each pair of adjacent radicals of R¹ to R⁸ is--CO--O--CO--; or at least one of R¹ to R⁸ is C₁ -C₂₀ alkyl--(X)_(p) --,C₂ -C₂₀ alkenyl--(X)_(p) --, C₂ -C₂₀ alkynyl--(X)_(p) --, C₃ -C₈cycloalkyl--(X)_(p) --, (C₁ -C₁₂ alkyl--C₃ -C₈ cycloalkyl--(X)_(p) --,C₃ -C₈ --cycloalkyl--CH₂ --(X)_(p) --, C₁ -C₁₂ alkyl--C₃ -C₈cycloalkyl--CH₂ --(X)_(p) --, C₆ -C₁₀ aryl--X--, C₇ -C₂₀ alkaryl--X--,C₇ -C₁₂ aralkyl--(X)_(p) -- or C₈ -C₂₀ alkaralkyl--(X)_(p) -- or--Y--(C_(m) H_(2m) --O)--_(n) R¹⁰ each of which is unsubstituted orsubstituted by --F, --OH, --CN, C₁ -C₁₂ alkoxy, C₁ -C₁₂ acyloxy or--COOR¹⁰ ; R¹⁰ is H or C₁ -C₁₈ alkyl, X is --O--, --S--, --SO-- or --SO₂-- and Y is --O-- or --S--, and p is 0 or 1, m is a number from 2 to 6and n is a number from 2 to 20; and R⁹ is C₁ -C₄ acyl which isunsubstituted or substituted by --F.

Where R¹ to R⁸ are --Si(C₁ -C₄ alkyl)₃, the alkyl group can be methyl,ethyl, n-propyl, isopropyl, n-butyl and isobutyl. --Si(CH₃)₃ isparticularly preferred.

Where R¹ to R⁸ are --COOR¹⁰, R¹⁰ can be linear or branched alkylpreferbly having 1 to 12 C atoms and particularly having 1 to 8 C atoms.Examples of alkyl are methyl, ethyl and the isomers of propyl, butyl,pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,tetradecyl, hexadecyl and octadecyl.

Within the scope of the preceding definitions, R¹ to R⁸ can besubstituted, preferably monosubstituted to trisubstituted andparticularly monosubstituted or disubstituted. Examples of suitablesubstituents are linear or branched alkoxy preferably having 1 to 6 Catoms and particularly having 1 to 4 C atoms. Ethoxy and methoxy areparticularly preferred.

Examples of suitable substituents are also acyloxy preferably having 1to 6 C atoms, for example C₁ -C₆ alkyl--COO-- or benzyloxy. Examples areformyloxy, acetoxy, trifluoroacetoxy, propionyloxy, acryloyloxy,methacryloyloxy and butanoyloxy.

The substituents can also be, for example, --COOR¹⁰ in which R¹⁰ ispreferably H or C₁ -C₄ alkyl.

In a preferred embodiment, R¹ to R⁸ can be substituted by --OH, --F, C₁-C₄ --alkoxy, --COO--(C₁ -C₄ alkyl) and C₁ -C₆ alkyl--CO--O--.

R¹ to R⁸ can be C₁ -C₂₀ alkyl--(X)_(p) --. The alkyl group can be linearor branched and preferably contains 1 to 18, particularly 1 to 12, andespecially 1 to 8, atoms. Examples of alkyl groups have been mentionedpreviously.

R¹ to R⁸ can be C₂ -C₂₀ alkenyl--(X)_(p) -- in which p is preferably 1,X is preferably --O-- and the alkenyl group preferably contains aterminal alkene group. The alkenyl group can be linear or branched andcan preferably contain 2 to 18, particularly 2 to 12, and especially 2to 6, C atoms. Examples are ethenyl, allyl, prop-1-en-1-yl,prop-1-en-2-yl, but-1-en-1- or -2- or -3- or -4-yl, but-2-en-1-yl,but-2-en-2-yl, pent-1-en-1- or -2- or -3- or -4- or -5-yl, pent-2-en-1-or -2- or -3- or -4- or -5-yl, hex-1-en-1- or -2- or -3-or -4- or -5- or-6-yl, hex-2-en-1- or -2- or - 3- or -4- or -5-or -6-yl, hex-3-en-1- or-2- or -3- or -4-or -5- or -6-yl, heptenyl, octenyl, nonenyl, decenyl,undecenyl, dodecenyl, tetradecenyl, hexadecenyl and octadecenyl.

R¹ to R⁸ can be C₂ -C₂₀ alkynyl--(X)_(p) -- in which p is preferably 1,X is preferably --O-- and the alkynyl group preferably contains aterminal alkyne group. The alkynyl group can be linear or branched andpreferably contains 2 to 18, particularly 2 to 12, and especially 2 to6, C atoms. Examples are ethinyl, propargyl, but-1-yn-3-yl,but-1-yn-4-yl, pent-1-yn-3- or -4- or -5-yl, hex-1-yn-3- or -4- or -5-or -6-yl, hex-2-yn-1- or -4- or -5- or -6-yl, hex-3-yn-1-yl,hex-3-yn-2-yl, heptynyl, octynyl, nonynyl, decynyl, undecynyl anddodecynyl. R¹ to R⁸ can be C₃ -C₈ cycloalkyl--(X)_(p) -- in which p ispreferably 1 and the cycloalkyl group preferably contains 3 to 6 Catoms, particularly 5 or 6 C atoms. Examples are cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl. R¹ toR⁸ can be (C₁ -C₁₂ alkyl)--C₃ -C₈ cycloalkyl--(X)_(p) -- in which thealkyl group preferably contains 1 to 6 C atoms, p is preferably 1 andthe cycloalkyl group is preferably cyclopentyl or cyclohexyl. Examplesare methylcyclopentyl, methylcyclohexyl, ethylcyclopentyl,ethylcyclohexyl, methylcyclopropyl and methylcyclobutyl.

R¹ to R⁸ can be C₃ -C₈ cycloalkyl--CH₂ --(X)_(p) --, preferably C₅ --orC₆ --cycloalkyl--CH₂ --(X)_(p) -- in which p is preferably 1.

R¹ to R⁸ can be (C₁ -C₁₂ alkyl)--C₃ -C₈ cycloalkyl--CH₂ --(X)_(p) -- inwhich p is preferably 1, the alkyl group preferably contains 1 to 6 Catoms and the cycloalkyl group is preferably cyclopentyl or cyclohexyl.Examples are methylcyclohexylmethyl or methylcyclohexylethyl.

Where R¹ to R⁸ are C₆ -C₁₀ aryl--X--, the aryl group is particularlynaphthyl and especially phenyl. Where R¹ to R⁸ are C₇ -C₂₀ alkaryl--X--,they are preferably (C₁ -C₁₄ alkyl)--phenyl--X-- in which the alkylgroup preferably has 1 to 8 C atoms and particularly 1 to 4 C atoms.

Where R¹ to R⁸ are C₇ -C₁₂ aralkyl--(X)_(p) --, they are preferablybenzyl--X-- or phenylethyl--X--.

Where R¹ to R⁸ are C₈ -C₂₀ alkaralkyl--(X)_(p) --, they are preferably(C₁ -C₁₃ alkyl)--benzyl--X-- in which the alkyl group containsespecially 1 to 6 C atoms. Examples are methylbenzyl--X-- andethylbenzyl--X--.

Where R¹ to R⁸ are --Y--(C_(m) H_(2m) --O)_(n) --R¹⁰, Y is preferably--O--, m is preferably 2 or 3 and n is preferably a number from 2 to 12,particularly 2 to 6, and R¹⁰ is preferably H or C₁ -C₄ alkyl. The C_(m)H_(2m) group is particularly ethylene or 1,2-propylene. R⁹ is preferablyC₁ acyl or C₂ acyl each of which is unsubstituted or substituted by F.Examples are butanoyl, propionyl, monofluoroacetoxy, difluoroacetoxy,formyloxy and particularly acetoxy and trifluoroacetoxy.

A preferred embodiment is constituted by compounds of the formula I inwhich R¹ to R⁸ independently of one another are H and at least one of R¹to R⁸ is a substituent belonging to the group --F, --Si(CH₃)₃,--COO--(C₁ -C₁₂ alkyl), C₁ -C₁₈ alkyl--(X)_(p) --, C₂ -C₁₈alkenyl--(X)_(p) --, C₂ -C₁₂ alkynyl--(X)_(p) --, C₆ -C₁₀ aryl--X--, C₇-C₁₈ alkaryl--X--, C₇ -C₁₀ aralkyl--(X)_(p) --, C₈ -C₁₈alkaralkyl--(X)_(p) -- or --Y--(C_(m) H_(2m) --O--)_(n) --R¹⁰ each ofwhich is unsubstituted or substituted by --F, C₁ -C₆ alkoxy, C₁ -C₆acyloxy or --COO--(C₁ -C₁₂ alkyl), R¹⁰ is H or C₁ -C₆ alkyl, X is --O--,--S--, --SO-- or --SO.sub. 2 -- and Y is --O-- or --S--, m is 2 or 3 andn is a number from 2 to 12 and p is 0 or 1 and R⁹ is acetyl which isunsubstituted or substituted by --F.

Another preferred embodiment is constituted by compounds of the formulaI in which R¹ and R⁴ to R⁸ are H; R² is --F, --CF₃, --COO--(C₁ -C₁₈alkyl) or C₁ -C₁₈ alkyl--X-- which is unsubstituted or substituted by--OH, --COO--(C₁ -C₆ alkyl) or C₁ -C₆ acyloxy; --Y--(CH₂ CH₂ O)_(n)--R¹⁰ in which Y is --O-- or --S--, R¹⁰ is H or C₁ -C₆ alkyl and n is anumber from 2 to 12; C₂ -C₁₂ alkenyl--CH₂ --X--; C₂ -C₁₂ alkynyl--CH₂--X--; phenyl--X--; C₁ -C₁₂ alkylphenyl--X--; benzyl--X--; or C₁ -C₁₂alkylbenzyl--X-- and R₃ is H or independently is the same as R₂, and Xis --O--, --S--, --SO-- or --SO.sub. 2 --.

As a substituent, R¹ is particularly --CF₃ or --COO--(C₁ -C₁₂ alkyl).

Preferred embodiments are also constituted by compounds of the formula Iin which a) R⁴, R⁵ and R⁸ are H, or b) R¹, R⁴, R⁵ and R⁸ are H, or c) R²and/or R³ are a substituent and R¹ and R⁴ to R⁸ are H, or d) R⁶ and/orR⁷ are a substituent and R¹ to R⁵ and R⁸ are H.

The invention also relates to a process for the preparation of compoundsof the formula I, which comprises reacting a substitutednaphthacene-5,12-dione of the formula II ##STR3## in which R¹ to R⁸ areas defined above, in a solvent and under reducing conditions, with ananhydride of the formula R⁹ CO--O--OCR⁹ in which R⁹ is as defined above.

Reductive acylation using reducing metals, for example zinc, is knownand has been described by T. Kametani in Chem. Pharm. Bull 26(12), pages3820-3825 (1978). The reduction can also be carried outelectrochemically or catalytically using noble metal catalysts, forexample Pt or Pd.

The catalytic reduction or the reduction with metals is advantageouslycarried out in the presence of an alkali metal salt of the carboxylicacid R⁹ COOH on which the anhydride of the formula R⁹ CO--O--OCR⁹ isbased. The alkali metal can, for example, be Li, Na, K, Rb or Cs.

The reaction is carried out in the presence of an inert solvent, forexample carboxylic acid esters, for example methyl or ethyl acetate. Bythis means, the reaction takes place under milder conditions and with ahigher yield than in the case of the known processes.

The reaction temperature can, for example, be 20° to 100° C. It isadvantageous to select a temperature within the range of roomtemperature, for example 20° to 40° C.

The substituted naphthacene-5,12-diones of the formula II are in partknown or they can be prepared by the processes described below.

The compounds of the formula II can, for example, be prepared bycarrying out a Friedel-Crafts reaction on a naphthalenedicarboxylicanhydride of the formula IV ##STR4## with a benzene of the formula V##STR5## in the presence of a Lewis acid, R¹ to R⁸ being as definedabove, and carrying out nucleophilic substitution on compounds of theformula I in which at least one of R¹ to R⁸ is --F. Compounds suitablefor the nucleophilic substitution are especially those of the formula(R¹ to R⁸)--X--H in which X is --O--, --S--, --SO-- or --SO₂ --, malonicacid esters or nitriles and phenylacetonitrile. These nucleophiliccompounds can be used in the form of their alkali metal salts, forexample, Li, Na or K salts. It is also possible to carry out thenucleophilic substitution in the presence of bases, for examplesolutions of alkali metal hydroxides or carbonates.

The compounds of the formula II can also be prepared by carrying out aDiels-Alder reaction on a compound of the formula VI ##STR6## in whichR⁵, R⁶, R⁷ and R⁸ are as defined above and X¹ and X² independently ofone another are --Cl, --Br or --I, with a compound of the formula VII##STR7## in which R¹, R², R³ and R⁴ are as defined above, withsubsequent elimination of HX¹ and HX². In the substituents R¹ to R⁸, pis preferably 1.

The reaction is advantageously carried out at temperatures from 50° to250° C., preferably 80° to 200° C. It is advantageous to use an inertsolvent, for example polar, aprotic solvents. Some examples are aromatichydrocarbons (benzene, toluene, xylene, chlorobenzene anddichlorobenzene), nitriles (actonitrile), ethers (dibutyl ether,dioxane, tetrahydrofuran, ethylene glycol dimethyl ether or diethyleneglycol dimethyl ether). Isolation and purification can be carried out bycustomary methods, for example crystallization, sublimation orchromatography.

Compounds of the formula VI are in part known (see, for example, H. P.Cava et al., J. Am. Chem. Soc., page 1701 (1957) and J. W. Barton etal., J. Chem. Soc. Perkin Trans. 1, pages 967-971 (1986)), or can beprepared by analogous processes. The 1,2-bis-(dichloromethyl ordibromomethyl)benzenes are also in part known or can be obtained bycustomary electrophilic or nucleophilic substitution reactions ofcorresponding o-dimethylbenzenes, followed by chlorination orbromination with, for example, N-chlorosuccinimide orN-bromosuccinimide.

The p-naphthoquinones of the formula VII are known and can be obtained,for example, by nucleophilic substitution of protected or unprotectedand substituted or unsubstituted halogeno-1,4-naphthoquinones ornitro-1,4-naphthoquinones with, for example, the compounds describedabove in the presence of alkali metal compounds (K₂ CO₃, CS₂ CO₃, KOH,NaOH, NaNH₂, NaOCH₃ or NaOC₂ H₅) or with alkali metal compounds, forexample those of Li, K, Na, Rb or Cs. Halogenonaphthoquinones andnitronaphthoquinones are described, for example, in Houben-Weyl,Quinones I, Volume 7/3b (1977). The naphthoquinones of the formula VIIcan also be prepared in a known manner by electrophilic or nucleophilicsubstitution of substituted or unsubstituted naphthalenes,dihydronaplthalenes or tetrahydronaphthalenes and subsequent conversioninto the substituted 1,4-napthoquinones.

The compounds of the formula II can also be prepared by reacting1,2-bis-(dihalogenomethyl)-benzenes of the formula ##STR8## in which Y¹is Cl, Br or I with a compound of the formula VII in the presence of NaIin an organic solvent. This method has been described by J. W. McOmie inSynthesis, pages 416-417 (1973).

Compounds of the formula II can also be prepared by reactinganthracene-1,4-quinones of the formula ##STR9## with an α-pyrone of theformula VIII ##STR10## or with a butadiene of the formula IX ##STR11##

R¹¹ being C₁ -C₆ alkyl, R¹⁰ being as defined above and preferably beingC₁ -C₆ alkyl. This method and the preparation of α-pyrones has beendescribed in U.S. Pat. No. 4,617,151 and in EP-A 0,195,743.

Compounds of the formulae VIII and IX can be obtained, for example, inthe following manner, X¹ being an alkali metal: ##STR12##

Where R¹ to R⁸ are a polyoxaalkylene radical, compounds of this type arealso obtained by reacting compounds of the formula I in which R¹ to R⁸are hydroxyalkyloxy with epoxides. It is also possible to modify theradicals R¹ to R⁸ by classic reactions, for example hydrolysis,esterification, transesterification, amidation, oxidation or reduction.Carboxylic acid esters can be converted into the trifluoromethylderivatives in a known manner by means of HF/SF₄.

The compounds of the formula I are obtained in short reaction times inhigh yields and in a high state of purity. Surprisingly, they aresuitable for direct reaction with sulfur with the formation oftetrathiotetracenes.

The invention also relates to a process for the preparation of5,6,11,12-tetrathiotetracenes of the formula III ##STR13## in which R¹to R⁸ independently of one another are H or a substituent belonging tothe group --F, --Si(C₁ -C₄ alkyl)₃ or --COOR¹⁰ ; or each pair adjacentradicals of R¹ to R⁸ is --CO--O--CO--; or R¹ to R⁸ are a substituentbelonging to the group C₁ -C₂₀ alkyl--(X)_(p) --, C₃ -C₈cycloalkyl--(X)_(p) --, C₁ -C₁₂ alkyl--C₃ -C₈ cycloalkyl--(X)_(p) --, C₃-C₈ cycloalkyl--CH₂ --(X)_(p) --, C₁ -C₁₂ alkyl--C₃ -C₈ cycloalkyl--CH₂--(X)_(p) --, C₆ -C₁₀ aryl--X--, C₇ -C₂₀ alkaryl--X--, C₇ -C₁₂aralkyl--(X)_(p) -- or C₈ -C₂₀ alkaralkyl--(X)_(p) -- or --Y--(C_(m)H_(2m) --O)_(n) --R¹⁰ each of which is unsubstituted or substituted by--F, --OH, C₁ -C₁₂ alkoxy, C₁ -C₁₂ acyloxy or --COOR¹⁰ ; R¹⁰ is H or C₁-C₁₈ alkyl, X is --O--, --S--, --SO-- or --SO₂ -- and Y is --O-- or--S--, and p is 0 or 1, m is a number from 2 to 6 and n is a number from2 to 20; which comprises reacting a compound of the formula Ia ##STR14##in which R¹ to R⁸ are as defined above and R⁹ is C₁ -C₄ acyl which isunsubstituted or substituted by --F, with sulfur in the presence ofcatalytic amounts of a sulfonic acid.

The reaction is advantageously carried out in a high-boiling solvent.Suitable solvents are, in particular, halogenated aromatic hydrocarbons,for example chlorobenzene, dichlorobenzenes and trichlorobenzenes, butalso nitrobenzene or Dowtherm A.

The reaction is also advantageously carried out under an inert gasatmosphere, for example using noble gases (helium, neon or argon) ornitrogen.

The reaction temperature is advantageously 100° to 250° C., especially150° to 250° C. It is advantageous to carry out the reaction at thereflux temperature of the solvent selected.

The amount of sulfonic acid can be 0.001 to 10 mol %, preferably 0.001to 5 mol % and especially 0.01 to 2 mol %, relative to the amount of thecompounds of the formula Ia.

Examples of suitable sulfonic acids are organic sulfonic acids,particularly aromatic sulfonic acids. Examples are methanesulfonic,ethanesulfonic, propanesulfonic, butanesulfonic, hexanesulfonic,trifluoromethanesulfonic or benzenesulfonic acid and especiallyp-toluenesulfonic acid.

The tetrathiotetracenes of the formula III are obtained in good yieldsby means of the process according to the invention. After beingisolated, they can be purified by means of customary methods, forexample by recrystallization or sublimation. In general, isolation iseffected by removing the solvent, washing the residue with a non-solventand drying.

Electrically conducting charge-transfer complexes (CT complexes) can beprepared from the compounds of the formula III by means of electronacceptors. They can be attached to polymers by means of their functionalsubstituents, for example incorporated into polymers as side groups (cf.U.S. Pat. No. 4,617,151). The CT complexes are also suitable for thepreparation of, for example, antistatic coatings of photographic filmelements, magnetic tapes, electrophotographic film elements andelectronic components (see U.S. Pat. No. 3,634,336). The chalcogenatedtetracenes also exhibit electrochromic properties; they can be used forelectrochromic displays. They are also suitable for use as laser-opticaldata storage units [Nach. Chem. Techn. Lab. 35, pages 255 et seq.(1987)] and as an anode material in organic solid state batteries (EP-A0,090,598). CT complexes of substituted tetrathiotetracenes ortetraselenotetracenes can also be incorporated into thermoplastic,thermosetting or elastomeric polymers in order to achieve antistaticproperties. This is effected advantageously, for example, by dissolvingthe substituted tetrathiotetracenes or tetraselenotetracenes, togetherwith a soluble polymer or a precursor thereof and an electron acceptor,for example an agent which forms halogen (organic halogenated compounds,for example bromoform, trichlorobromomethane, tetrabromomethane,hexachloropropane, perchlorobutadiene, 1,3-dichloro-2-butene,1,4-dichloro-2-butene, 1,4-bis-(trichloromethyl)-benzene,iodoacetonitrile, iodoform, tetrachloroethylene,perchlorocyclobutadiene, N-chlorosuccinimide, N-bromosuccinimide orN-iodosuccinimide), if appropriate together with a further inertsolvent, and removing by evaporation at an elevated temperature theagent which forms halogen and the solvent. The resulting compositioncontains a network of needle-shaped crystals of the CT complex in thepolymer, if the chalcogenated tetracene is unsubstituted or containssmall substituents (for example F, CH₃ or CF₃). Compositions of thistype exhibit a high electrical conductivity. This can be improvedfurther if a substituted tetrathiotetracene or tetraselenotetracene ofthe formula III which does not form such a network and which is presentin the polymer matrix in finely divided form is concomitantly used,since substituted tetrathiotetracenes or tetraselenotetracenes of thistype have no tendency, or only a slight tendency, to crystallize in thepolymer.

The following examples illustrate the invention in greater detail.

A) PREPARATION EXAMPLES Examples 1-22

31.05 mmol of zinc powder are added with stirring to 10.35 mmole of2-substituted naphthacene-5,12-dione, 40 ml of ethyl acetate, 25 ml ofacetic anhydride and 31.05 mmol of potassium acetate. After beingstirred for 40 minutes at 25° C., the reaction mixture is filtered andthe residue is washed four times with CH₂ Cl₂. The filtrates areevaporated and the residue is recrystallized from CH₂ Cl₂ /pentane andthen from toluene. The yields and melting points of the 2-substituted5,12-diacetoxynaphthacenes obtained are shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________     ##STR15##                                                                    Example No.                                                                          R                Yield (%)                                                                           Melting point (°C.)                      __________________________________________________________________________     1     OCH.sub.3        81    247-252                                          2     OCH.sub.2 CH.sub.3                                                                             79    150-153                                          3     OCH.sub.2 CH(C.sub.2 H.sub.5)(CH.sub.2).sub.3 CH.sub.3                                         71    130-135                                          4     On-C.sub.8 H.sub.17                                                                            84    107-111                                          5     OCH(CH.sub.3).sub.2                                                                            61    215-218                                          6     On-C.sub.18 H.sub.37                                                                           49    155-157                                          7     OCH.sub.2 CHCH.sub.2                                                                           74    200-201                                          8     OCH.sub.2 CCH    59    213-215                                          9     OCH.sub.2 CH.sub.2 OH                                                                          47    189-193                                         10     O(CH.sub.2).sub.4 OH                                                                           36    181-183                                         11     O(CH.sub.2).sub.2 O(CH.sub.2).sub.2 OH                                                         28    149-152                                         12     SO.sub.2 CH.sub.3                                                                              69    >250                                            13     SCH.sub.2 CH.sub.3                                                                             77    130-135                                         14                                                                                    ##STR16##       79    145-150                                         15                                                                                    ##STR17##       82    >220 (decomposition)                            16     F                73    170-175                                         17     C(CH.sub.3)(COOC.sub.2 H.sub.5).sub.2                                                          63    230 (decomposition)                             18     CF.sub.3         91    >250                                            19     COOCH.sub.3      81    185-190                                         20     COO(CH.sub.2).sub.3 CH.sub.3                                                                   73    195-196                                         21     COO(CH.sub.2).sub.7 CH.sub.3                                                                   61    143-145                                         22     COOCH.sub.2 CH(C.sub.2 H.sub.5)(CH.sub.2).sub.3 CH.sub.3                                       45    149-150                                         __________________________________________________________________________

The corresponding 2-substituted naphthacene-5,12-diones of Examples 1-15and 17 can be obtained by nucleophilic substitution of2-fluoronaphthacene-5,12-dione.

2-(Trifluoromethyl)-naphthacene-5,12-dione

5.65 g (25 mmol) of 6-(trifluoromethyl)-1,4-naphthoquinone, 9.82 g(approx. 37 mmol) of 1,2-dibromobenzocyclobutene (containing a little2-bromo-1-iodobenzocyclobutene as an impurity) and 100 ml of xylene arekept under reflux for 16 hours, using a water separator. The mixture iscooled and the precipitate is filtered off and washed with xylene. Yield5.82 g (71%); melting poing 253°-254° C.

An analogous procedure is used in the preparation of2,3-bis-(trifluoromethyl)-naphthacene-5,12-dione (yield 59%; meltingpoint >280° C.); methyl1-(trifluoromethyl)-naphthacene-5,12-dione-3-carboxylate (yield 60%;melting point 234°-235°) and methyl2-ethoxynaphthacene-5,12-dione-3-carboxylate (yield 30%; melting point192°-194° C.), which are used in the following examples 24-26.

Examples 23-27

1.65 mmol of 2-substituted naphthacene-5,12-dione, 5 ml of ethylacetate, 4.96 mmol of potassium acetate and 3 ml of acetic anhydride arehydrogenated for 35 minutes at 20°-25° C., with the addition of 0.1 g ofPd/C (5%). The mixture is filtered and the residue is washed three timeswith CH₂ Cl₂. The filtrates are concentrated, and the residue isrecrystallized from CH₂ Cl₂ /pentane. The yields and melting points ofthe 5,12-diacetoxynaphthacenes obtained are indicated in Table 2.

                  TABLE 2                                                         ______________________________________                                         ##STR18##                                                                    Ex-                                     Melting                               ample                             Yield point                                 No.   R.sup.1 R.sup.2    R.sup.3  %     (°C.)                          ______________________________________                                        23    H       OCH.sub.2 CH.sub.3                                                                       H        70    149-153                               24    H       CF.sub.3   CF.sub.3 76    >250                                  25    CF.sub.3                                                                              H          COOCH.sub.3                                                                            18    >280                                  26    H       OCH.sub.2 CH.sub.3                                                                       COOC.sub.2 H.sub.5                                                                     65    208-210                               .sup. 27.sup.a                                                                      H       CH.sub.3   CH.sub.3 40    >250                                  ______________________________________                                         .sup.a 2,3-Dimethylnaphthacene-5,12-dione is obtained by subjecting           1,2di-bromobenzocyclobutene to a condensation reaction with                   6,7dimethyl-naphthalene-1,4-dione with subsequent elimination of 2 HBr in     situ.                                                                    

Example 28

A solution of 400 ml of acetic anhydride and 11.1 g (0.04 mol) oftetrabutylammonium chloride is introduced into a cell divided by a D3glass frit and equipped with a stainless steel cathode shaped in theform of a stirrer and a Pt anode. 3 g (0.67 mmol) of2-(4-hydroxybutoxy)-naphthacene-5,12-dione are then added under nitrogenand electrolysis is carried out for 20 hours at a current of 20 mA. Thesolution in the cathode compartment is then poured into ice water andneutralized with saturated sodium carbonate solution. The precipitatedproduct is filtered off and washed with water. Yield 3.8 g (90.5%) of2-(4'-acetoxybutoxy)-5,12-diacetoxynaphthacene. Mass spectrum: M⁺ =474

Elemental analysis: calculated: % C 70.87, % H 5.52, % O 23.60, found: %C 70.20, % H 5.60, % O 23.66.

Example 29 2-Ethoxy-5,12-bis-(trifluoroacetoxy)-naphthacene

2 g (6.62 mmol) of 2-ethoxynaphthacene-5,12-dione, 55 ml oftrifluoroacetic anhydride, 2.7 g of sodium trifluoroacetate, 20 ml ofethyl acetate and 1.08 g (16.54 mmol) of zinc dust are stirred for 3hours at 25°-30° C. The mixture is filtered and the residue is washedseveral times with tetrahydrofuran/CH₂ Cl₂. The filtrates are evaporatedand the residue is triturated with diethyl ether. The crystals arefiltered off and recrystallized from toluene: yield 2.83 g (86%);melting point 165°-70° C.

Examples 30-36

1.83 mmol of substituted naphthacene-5,12-diacetate, 15.8milliequivalents of S₈ and 0.026 mmol of p-toluenesulfonic acid in 100ml of 1,2,4-trichlorobenzene are heated under a reflux, with a gentleflow of argon, in a 250 ml flask equipped with a reflux condenser and agas inlet tube. The dark green solution is then evaporated under a highvacuum.

The crude product is chromatographed with CCl₄ over a silica gel flashcolumn (240 g of silica gel, .0.0.7 cm). [The silica gel must be treatedbeforehand with CCl₄ containing 2% of triethylamine and must then bewashed with pure CCl₄ until the eluate is again neutral.] The fractionsof a dark green colour contain the purified 2-substituted5,6,11,12-tetrathiotetracene. Spectral data and yields are shown inTable 3.

                                      TABLE 3                                     __________________________________________________________________________     ##STR19##                                                                    Example No.                                                                          R              Mass spectrum (M.sup.+)                                                                  λ.sub.max (nm) in                                                      1,2,4-tri-chlorobenzene                                                                        Yield                       __________________________________________________________________________                                                      (%)                         30     OC.sub.2 H.sub.5                                                                             396        700              24.sup.a)                   31     O-n-C.sub. 8 H.sub.17                                                                        480        699              50.sup.b)                   32     OCH.sub.2 CH(C.sub.2 H.sub.5)(CH.sub.2).sub.3 CH.sub.3                                       480        698               8.sup.a)                   33     O-n-C.sub. 18 H.sub.37                                                                       620        698              50.sup.a)                   34     C(CH.sub.3)(COOC.sub.2 H.sub.5).sub.2                                                        524        704              10.sup.a)                   35     COO(CH.sub.2).sub.3 CH.sub.3                                                                 452        745              82% (crude)                 36     SC.sub.2 H.sub.5                                                                             412        711               3%.sup.a)                  __________________________________________________________________________     .sup.a) sublimed                                                              .sup.b) chromatographed                                                  

Example 37

251 mg (0.61 mmol) of 2-trifluoromethylnaphthacene-5,12-diacetate, 78 mg(2.43 milliequivalents) of S₈ and 2 mg (0.01 mmol) of p-toluenesulfonicacid in 35 ml of 1,2,4-trichlorobenzene are heated under reflux for 20hours, with a gentle flow of argon, in a 100 ml flask equipped with areflux condenser and a gas inlet tube. After cooling, the solvent isremoved by evaporation under high vacuum (HV), the residue is boiledwith hexane, and the black powder is filtered off and dried at 60° C.under HV. 203 mg (79%) of crude product are obtained.

This product is sublimed at 190° C. (1.3×10⁻⁴ mbar), and 67.5 mg (35.6%)of pure 2-trifluoromethyl-5,6-11,12-tetrathiotetracene are obtained(small black needles). Mass spectrum: M⁺ =420. λ_(max)(1,2,4-trichlorobenzene): 725, 665 and 484 nm.

Example 38 2,3-trifluoromethyl-5,6,11,12-tetrathiotetracene

The procedure followed is as in Example 37, and2,3-trifluoromethylnaphthacene-5,12-diacetate is used. Yield: 75.6 mg(30%) after sublimation.

Mass spectrum: M⁺ =488. λ_(max) (1,2,4-trichlorobenzene): 755 nm.

B) Use examples Example 39 Electrochromism

1 mg of 2,3-di-(trifluoromethyl)-5,6,11,12-tetrathiotetracene and 100 mgof LiClO₄, dissolved in 5 ml of acetone, are filled into the anode side,and a solution of 1 mg of2,3-di-(trifluoromethyl)-5,6,11,12-tetrathiotetracene perchlorate (CTcomplex, for preparation see U.S. Pat. No. 3,634,336) and 100 mg ofLiClO₄ in 5 ml of acetone are filled into the cathode side of anelectrochromic cell consisting of a Teflon membrane and an anode andcathode of ITO glass, each at a distance of 0.5 mm. After a voltage of 2volts has been applied, the colours change, in the course of a fewseconds, from green to red-violet on the anode side and from red-violetto green on the cathode side. The original colours are obtained in bothhalves of the cell by reversing the polarity of the voltage. The sameeffect is observed if nitrobenzene or dimethylformamide is used as thesolvent.

What is claimed is:
 1. A compound of the formula I ##STR20## in which R¹to R⁸ independently of one another are H and at least one of R¹ to R⁸ is--F, --Si(C₁ -C₄ alkyl)₃ or --COOR¹⁰ ; or each pair of adjacent radicalsof R¹ to R⁸ is --CO--O--CO--; or at least one of R¹ to R⁸ is C₁ -C₂₀alkyl--(X)_(p) --, C₂ -C₂₀ alkenyl--(X)_(p) --, C₂ -C₂₀ alkynyl--(X)_(p)--, C₃ -C₈ cycloalkyl--(X)_(p) --, C₁ -C₁₂ alkyl--C₃ -C₈cycloalkyl--(X)_(p) --, C₃ -C₈ --cycloalkyl--CH₂ (X)_(p) --, C₁ -C₁₂alkyl--C₃ -C₈ cycloalkyl--CH₂ --(X)_(p) --, C₆ -C₁₀ aryl--X--, C₇ -C₂₀alkaryl--X--, C₇ -C₁₂ aralkyl--(X)_(p) -- or C₈ -C₂₀ alkaralkyl--(X)_(p) -- or --Y--(C_(m) H_(2m) --O)_(n) --R¹⁰ each of which isunsubstituted or substituted by --F, --OH, --CN, C₁ -C₁₂ alkoxy, C₁ -C₁₂acyloxy or --COOR¹⁰ ; R¹⁰ is H or C₁ -C₁₈ alkyl, X is --O--, --S--,--SO-- or --SO₂ -- and Y is --O-- or --S--, and p is 0 or 1, m is anumber from 2 to 6 and n is a number from 2 to 20; and R⁹ is C₁ -C₄ acylwhich is unsubstituted or substituted by -F, provided that when R¹ -R⁶and R⁸ are H and, R⁷ is methyl, R⁹ is not C₂ -acyl.
 2. A compoundaccording to claim 1, in which R¹ to R⁸ independently of one another areH and at least one of R¹ to R⁸ is --F, --Si(CH₃)₃, --COO--(C₁ -C₁₂alkyl), or at least one of R¹ to R⁸ is C₁ -C₁₈ alkyl--(X)_(p) --, C₂-C₁₈ alkenyl--(X)_(p) --, C₂ -C₁₂ alkynyl--(X)_(p) --, C₆ -C₁₀aryl--X--, C₇ -C₁₈ alkaryl--X--, C₇ -C₁₀ aralkyl--(X)_(p) --, C₈ -C₁₈alkaralkyl--(X)_(p) -- or --Y--(C_(m) H_(2m) --O--)_(n) --R¹⁰ each ofwhich is unsubstituted or subtituted by --F, C₁ -C₆ alkoxy, C₁ -C₆acyloxy or --COO--(C₁ -C₁₂ alkyl), R¹⁰ is H or C₁ -C₆ alkyl, X is --O--,--S--, --SO-- or --SO₂ -- and Y is --O-- or --S--, m is 2 or 3 and n isa number from 2 to 12 and p is 0 or 1 and R⁹ is acetyl which isunsubstituted or substituted by --F.
 3. A compound according to claim 1,in which R⁴, R⁵ and R⁸ are H.
 4. A compound according to claim 1, inwhich R¹, R⁴, R⁵ and R⁸ are H.
 5. A compound according to claim 1, inwhich R², R³ R² and R³ are --F, --Si(C₁ -C₄ alkyl)₃ or --COOR¹⁰, and R¹and R⁴ to R⁸ are H.
 6. A compound according to claim 1, in which R⁶, R⁷or R⁶ and R⁷ are --F,--Si(C_(1`-C) ₄ alkyl)₃ or --COOR¹⁰, and R¹ to R⁵and R⁸ are H.
 7. A compound according to claim 1, in which R¹ is --CF₃or --COO--(C₁ -C₁₂ alkyl).
 8. A compound according to claim 1, in whichR¹ and R⁴ to R⁸ are H; R² is --F, --CF₃, --COO--(C₁ -C₁₈ alkyl) or C₁-C₁₈ alkyl--X-- which is unsubstituted or substituted by --OH,--COO--(C₁ -C₆ alkyl) or C₁ -C₆ acyloxy; --Y--(C₂ C₂ O)_(n) --R¹⁰ inwhich Y is --O-- or --S--, R¹⁰ is H or C₁ -C₆ alkyl and n is a numberfrom 2 to 12; C₂ -C₁₂ alkenyl--CH₂ --X--; C₂ --C₁₂ alkynyl--CH₂ --X--;phenyl--X--; C₁ -C₁₂ --alkylphenyl--X--; benzyl--X--; or C₁ -C₁₂alkylbenzyl--X-- and R₃ H or independently is the same as R₂, and X is--O--, --S--, --SO-- or --SO₂ --.